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Multiple-Input Buck Boost Power Converter A power converter circuit to convert multiple direct current (dc) inputs to one or more dc outputs. This dc-dc power converter allows its load to be powered by multiple,... Read More A power converter circuit to convert multiple direct current (dc) inputs to one or more dc outputs. This dc-dc power converter allows its load to be powered by multiple, different sources of various voltage and current levels (such as solar panels, batteries, fuel cells, etc.). This converter has both buck and boost capability. This circuit can simultaneously draw power from several dc electrical energy sources of different kinds (such as solar panels, batteries, fuel cells, etc.). The circuit topology is capable of an arbitrary number of input sources of different voltage/current/power levels. There is a single output voltage that can directly supply a load, or can supply another power converter. The default circuit uses an inductor, but it may be substituted with a transformer to provide electrical isolation or multiple output as well. The power flow from each source can be controlled separately in order to optimize the power flow characteristics for cost, environmental protection, or any other performance objective. Low power applications regulate source switching with a control circuit. High power applications regulate and optimize flow characteristics with a digital signal processor (DSP). This circuit contains a minimum number of components which reduce overall complexity and cost when compared to other implementations. In addition, due to efficiency in design, this circuit can be scaled to work across a multitude of power ranges. Applications: This technology can be used in any application which uses multiple dc energy sources and in situations where backup or simultaneous alternative energy sources are used. Such sources include solar cells, fuel cells, batteries, and thermoelectric sources. Benefits: Simple: Designed with minimal parts, allowing for reduced complexity in design and higher reliability. Low Cost: Requires fewer inductors and transistors when compared to equivalent dc-dc converters, therefore manufacturing costs are reduced. Efficient: Less loss and higher conversion efficiency due to the minimal design parts. Adaptable: Easily integrated into existing systems and combined with other converters (i.e. ac-dc). To license the entire Solar Panels portfolio, click here.
Method for Isolating Antennas Using Meandered-Line Ground Plane Surface Wave Filter A wireless communication device includes multiple antennas spaced apart from each other. Also included is a dielectric substrate with electrically conductive... Read More A wireless communication device includes multiple antennas spaced apart from each other. Also included is a dielectric substrate with electrically conductive ground areas along the substrate opposite the antennas. Signal coupling is decreased between the antennas by connecting the ground areas together with an isolation structure. In one nonlimiting form, this structure includes an electrically conductive meander line structure.
An Internally Heated Shape Memory Polymer Dry Adhesive Dr. Kim from the University of Illinois has developed a 2-part dry adhesive which has an electrically conductive layer and an adhesive layer. The electrically... Read More Dr. Kim from the University of Illinois has developed a 2-part dry adhesive which has an electrically conductive layer and an adhesive layer. The electrically conductive layer is made from carbon black and shape memory polymer (SMP), while the adhesive layer is made of SMP. Applying voltage to the adhesive strips allows the SMP to bond to both curved and flat surfaces. Re-application of voltage allows the adhesive to be removed. This technology represents improvements over current dry adhesives because of the internal heating capability, reversibility of shape before and after bonding and reusability.
Multiple-Carrier Pulse Width Modulation for Inverter Operation A method for generating pulse width modulated control signal has the steps of providing a base carrier waveform, segmenting the base carrier waveform into a plurality of... Read More A method for generating pulse width modulated control signal has the steps of providing a base carrier waveform, segmenting the base carrier waveform into a plurality of carrier waveforms, and providing at least one modulating signal. The first and second waveforms are compared to the at least one modulating signal to produce first and second comparator outputs, which are then mathematically combined to produce a pulse width modulated control signal. The technology is a process that can be applied to dc-ac power converters (i.e., inverters) that use pulse width modulation (PWM), to provide two features: It allows inverters to use a high-frequency ac link bus instead of the conventional dc; and, It allows multiple signals to be put onto the same PWM carrier or data stream for delivery to multiple switches. To license the entire Solar Panels portfolio, click here.
A Method for Compensating Wave Reflections in Transmission Lines This technology is a method to eliminate voltage overshoot in cables used to connect AC electric motors and pulse width modulation (PWM) inverters. As a function... Read More This technology is a method to eliminate voltage overshoot in cables used to connect AC electric motors and pulse width modulation (PWM) inverters. As a function of cable length and voltage rise time, voltage overshoot occurs when high frequency currents reflect between the motor and source ends of a cable. University of Illinois researchers have devised a compensator that shapes the output of the PWM inverter in order to eliminate these reflections; the method only requires knowledge of the transmission line characteristic impedance and propagation delay. This technique extends the life of motor insulation and protects voltage-sensitive devices. Voltage overshoot occurs when high frequency currents reflect between the motor and source ends of an electrical cable. Reflective waves of current can build up, causing motor insulation failure as well as damage to voltage-sensitive devices. While there have been techniques developed to compensate for voltage overshoot, many are complex, need load characteristics, and often require the use of bulky and expensive equipment. The University of Illinois technique provides a mathematically exact solution that modifies the output of the PWM inverter in order to eliminate wave reflection. This technique is designed to eliminate voltage overshoot in the cable that connects alternating current (AC) electric motors to pulse width modulation (PWM) inverters that use insulated gate bipolar transistors (IGBT). IGBT motor drive cables are particularly susceptible to voltage overshoot due to their extremely fast switching speeds. The compensator, which attaches to either the source or motor end of a cable, is a filter that uses an appropriate linear combination of voltages and currents to transform the transmission line into a pure delay transfer. This prevents wave reflection and thus voltage overshoot. Users do not need to know the motor or drives characteristics; however, they do need to know the transmission line impedance and the propagation delay in order to use this device. This invention improves on existing solutions to voltage overshoot by providing an exact solution rather than approximation. Applications: The range of applications that use AC motors is vast, examples include: Heavy Industrial Machines or Manufacture: Heavy industries including automotive, materials handling, mining operations, plastic and rubber production, ceramics, textile, and utilities. Workshops: Metalworking, printing and woodworking shops. Chemical Industries: Chemical refining, pharmaceutical production, and plastic fabrication. Benefits Cost-Effective: Eliminates damaging wave reflection, prolonging the usefulness of motors and voltage-sensitive devices. Low-Cost and Small: No large or expensive equipment is needed to implement this technology. Self-Adapting: Modifies waveform as transmission cable properties change over time. Versatile: Can be implemented at either the motor or source side of a cable, allowing users to select the side that is easier to maintain.
Series-Input Parallel Output Multiple DC-DC Converter with Dynamic Current Sharing for High-Current DC Power Supply The combination of a unique series-input parallel-output (SIPO) circuit configuration and a sensorless current mode (SCM) technique ensures automatic and nearly perfect... Read More The combination of a unique series-input parallel-output (SIPO) circuit configuration and a sensorless current mode (SCM) technique ensures automatic and nearly perfect load sharing of multiple dc:dc converters even during fast dynamic changes. A power supply in an embodiment of the invention includes a plurality of dc--dc switching power converters, each of which has its input isolated from its output. The power converters are arranged with their respective inputs being series connected and their respective outputs being parallel connected in an embodiment of the invention. In another embodiment of the inputs are parallel connected and the outputs series connected. Each power converter includes an input filter in each of said dc--dc switching power converters and an output filter. Each power converter includes a sensorless current mode control circuit controlling its switching duty ratio. To license the entire Solar Panels portfolio, click here.
Commutation technique for an ac-to-ac converter based on state machine control This invention is a technique that resolves current commutation challenges in various types of ac-ac switching power converters. It also applies to inverters and... Read More This invention is a technique that resolves current commutation challenges in various types of ac-ac switching power converters. It also applies to inverters and rectifiers with high-frequency links. Direct ac-ac converters such as matrix converters and cycloconverters benefit from the approach. This technology commutates load current without inserting dead-time into the switching sequence or using large inductors to limit shoot-through current. Both of these prior techniques intrinsically compromise a converter's performance and efficiency. The new technology provides a continuous path for load current and control of ac-ac converter switching so voltage sources do not short-circuit during commutation. If input voltage sources short-circuit they result in dangerously high shoot-through currents, while a disruption in the load current results in dangerously high voltages.Either scenario can damage or destroy equipment. In the past, additional components or timing constraints have been required to address current commutation. This new technology prevents both shoot-through and load current disruption, and allows load-current zero-crossings to occur naturally without the distortion associated with prior techniques. The preferred embodiment of the new invention is a state-machine-based controller that tracks the switch sequencing needed to avoid trouble. Applications Link inverters - The high-frequency link pulse width modulation (HF PWM) topology is a reduced-cost solution ideal for producing ac voltage from alternative energy sources such as solar panels and fuel cells. Other applications include uninterruptible power supplies (UPS), portable generators, and inverters for automobiles. Matrix converters - ac-ac converters based on direct switch matrix circuits are difficult to implement with conventional commutation methods. The invention facilitates the design and operation of matrix converters. Cycloconverters - Applications for cycloconverter-type ac-ac converters have traditionally been limited to relatively low frequencies, in part because of complicated current management. Effective commutation has been a significant barrier to wider application of these circuits. This invention resolves the commutation challenge and greatly expands the application range of cycloconverters. Benefits Smooth half-cycle transitions - Proper selection of switch sequencing allows a load current to transition smoothly from one half-cycle to the next without disruptions. Reduced distortion and EMI - Smooth current zero-cross transitions eliminate distortion inherent with dead-time techniques. Natural current commutation provides superior EMI performance compared with forced current commutation. Increased conversion and cost efficiency - The new technology facilitates increased power conversion efficiency while supporting miniaturization. It reduces cost by reducing the need for commutation chokes or large snubbers. Protects equipment - This technology prevents current shoot-through and load current disruptions that damage equipment. To license the entire Solar Panels portfolio, click here.
Control Methods and Circuits for Extremely Fast Response in Switching Power Converters A method for accomplishing energy changes for a power converter to minimize an impact of a disturbance. The power converter includes energy storage and switches.... Read More A method for accomplishing energy changes for a power converter to minimize an impact of a disturbance. The power converter includes energy storage and switches. The method comprises determining a nature of the disturbance, evaluating an amount of energy to be added or removed from the internal storage, and computing operating times of the switches to minimize the impact of the disturbance on outputs of the power converter.
Trade-off Method for Power Factor Correction The invention recognizes that filter size can be reduced substantially as power factor is permitted to deviate below unity in systematic ways. Preferred methods of the... Read More The invention recognizes that filter size can be reduced substantially as power factor is permitted to deviate below unity in systematic ways. Preferred methods of the invention provide specific, computable waveforms that permit use of a minimum filter size given a desired target power factor. To license the entire Solar Panels portfolio, click here.
Multiple-use Corn zein-based Biodegradable Resins, Sheets, and Films are an attractive alternative to plastic This technology is a process for preparing biodegradable resins comprised of corn zein and fatty acids and forming the resins into sheets, thin films, and similar... Read More This technology is a process for preparing biodegradable resins comprised of corn zein and fatty acids and forming the resins into sheets, thin films, and similar products useful in a broad range of food packaging and agricultural applications. Corn zein-based Biodegradable Resins present an environmentally friendly alternative to plastic. Zein resins are new products derived from corn zein. Zein, a family of proteins found in corn, is solvent extracted, mixed with long chain fatty acids, chilled, washed and kneaded to form a moldable biodegradable plastic which can be extruded immediately to form products or pellitized for later use. Pellets can be stored or shipped to plastic mills to be formed into highly useable, edible, biodegradable, environmentally friendly products. Applications Consumer Replacement for plastic packaging materials such as trash and grocery bags; shrink films used to protect palletized products; food wraps used to prevent spoilage; or disposable food service ware such as plates, bowls, and cups. Agricultural Weed Control: Rolled films produced from zein resin can be applied to planting beds or placed between row crops to prevent weeds. Since the product is fully biodegradable, there's no need to remove the preventative layer at the end of the growing season; saving time and money. Cover for Round Hay Bales: Zein-based resin films can be used to protect hay bales from spoiling. Zein-based resins are completely edible; therefore, films do not need to be removed prior to their use. Horticulture Containers manufactured from zein-based resins go directly from the green-house to a consumer's garden or planting bed, saving disposal of traditional plastic pots. Benefits Multiple End-Use Products: Products manufactured from zein-based resins can be extruded, blown, or injection molded into a wide variety of forms. Examples include trays, bowls, clamshells, films which can be used for wraps and/or laminated, and edible hay bale wrappers. Desirable Production Characteristics: Zein bioplastics are flexible, tough, heat sealable, able to accept color pigmentation, and producible in varying degrees of oxygen and carbon dioxide permeability. Fully Biodegradable: Unlike commodity plastics that do not degrade, products manufactured from zein-based resins are completely biodegradable by native soil microflora; leaving no residual materials to dispose of or fear of ingestion by wildlife or production animals. Abundance of Raw Material: Zein resins are derived from corn. Zein-based resins are categorized by the FDA as "Generally Recognized as Safe" (GRAS): Products manufactured from zein-based resins can be used to package and/or protect food stuffs.

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